How I Killed Pluto and Why It Had It Coming (30 page)

Like most marchers in the Doo Dah Parade, we got quizzical looks, a few claps, a smattering of boos, and a lot of tortillas thrown at us. I spent most of my time trying to make sure Lilah didn’t pick them up and eat them. But still, Pluto was dead, and it was good to participate in its burial.

•   •   •

But not everyone was ready to bury Pluto just yet.

On the very day of the vote to demote Pluto and Eris, a few astronomers began collecting signatures protesting the details of the IAU decision. They issued a simple statement:

It’s hard to argue with that statement. As much as I am proud of the astronomers who had the guts to go against emotional sentiment and to remake the solar system correctly, the actual definition by which they did it is pretty clunky. In fact, I won’t use it, either.

In the question-and-answer session of a recent talk I gave at Sarah Lawrence College, a very agitated young woman raised her
hand and began to read from notes: “In the IAU definition of the word ‘planet’ it says you have to be three things to be a planet …”

“Wait, wait, wait,” I said. “Before you even start, let me tell you why you should
never
think about the IAU definition of the word ‘planet.’ ”

In the entire field of astronomy, there is no word other than
planet
that has a precise, lawyerly definition, in which certain criteria are specifically enumerated. Why does
planet
have such a definition but
star, galaxy
, and
giant molecular cloud
do not? Because in astronomy, as in most sciences, scientists work by concepts rather than by definitions. The concept of a star is clear; a star is a collection of gas with fusion reactions in the interior giving off energy. A galaxy is a large, bound collection of stars. A giant molecular cloud is a giant cloud of molecules. The concept of a planet—in the eight-planet solar system—is equally simple to state. A planet is one of a small number of bodies that dominates a planetary system. That is a concept, not a definition. How would you write that down in a precise definition?

I wouldn’t. Once you write down a definition with lawyerly precision, you get the lawyers involved in deciding whether or not your objects are planets. Astronomers work in concepts. We rarely call in the attorneys for adjudication.

The young woman in the audience was not satisfied.

“You can’t just dismiss the definition. The definition is the reason that Pluto is no longer a planet!”

I tried to explain to her that the
concept
, not the definition, is the reason that Pluto is not a planet. The definition was simply a poor attempt at codifying the concept.

She went on: “But by part three of the definition even Jupiter is not a planet!”

The young woman could probably make a reasonable case in
court for her strict reading of the definition. But when the case was appealed to the Supreme Court—and it certainly would be—some justices might try to discern the original intent of the definers. I am certain that it was not anyone’s intent to exclude Jupiter from being a planet. The original intent was simply an attempt to describe the eight-planet solar system. The case for a strict reading of the definition would ultimately be tossed out. And then, if the justices were wise, they would also toss out the definition altogether. We’re better off without one. Pluto is not a planet not because it fails to meet the three-headed criteria laid out by the IAU. Pluto is not a planet because the criteria were written to try to explain the concept that Pluto is not a planet.

•   •   •

But the astronomers who organized the petition saying that they would never use the IAU definition were not quibbling over the logic of having a definition in the first place. They wanted the eight-planet solar system overturned. They wanted Pluto resurrected. While most of the rest of the astronomical world has acknowledged the reasonableness of the decision and moved on, a small group is continuing to try to have Pluto make a comeback.

Over the months and years, their arguments have changed, in the attempt to get some traction. At first, they took a line straight from the people trying to get creationism taught alongside evolution in schools: “Teach the controversy!” they said. Then they argued that the IAU decision was undemocratic because many of the members of the IAU had not been there that day to vote. The complaint is true, but the implication that the outcome would have been different is quite a stretch. Sometimes the argument is that only
planetary
astronomers are qualified to make the decision—again, as if that would make a difference. In my unscientific poll of seven professors of planetary science who
happen to work on the same floor as I do, all seven thought that eight planets make the most sense.

Particularly amusing to me was the complaint about the phrase
dwarf planet
. By the simple rules of grammar, a dwarf planet is a planet, they would say. The fact that the IAU would say that a dwarf planet is not a planet demonstrates that the entire decision must be wrong. What no one making these arguments remembers—or admits to remembering—is that the only people who liked the phrase
dwarf planet
at first were the ones who hoped that it would save Pluto when the other planets were renamed “classical planets.” Yet Resolution 5B was a specific vote on this issue, and it clearly stated that dwarf planets are not planets—just as Matchbox cars are not cars, stuffed animals are not animals, and chocolate bunnies are not bunnies. I don’t particularly like the phrase
dwarf planet
, either, but it is serviceable.

I’ve heard the argument that the definition is unworkable because it is inconsistent with the rest of astronomy. Nowhere else in astronomy, some say, do you classify an object by its relationship to its neighbors instead of by its own individual properties. Therefore the only definition that makes sense is that all round things are planets, regardless of where they find themselves. Well, not all round things are planets, just round things that orbit stars. And what if the round thing orbits another round thing? Well, then it is a moon, of course. But but but, doesn’t that violate the rule that things aren’t defined in relationship to other things? Well, yes, but that’s just common sense, they would say. Okay. Got it.

•   •   •

A few weeks after Xena became Eris, I received a note from a friend:

The Spanish? I hadn’t thought much about them in the preceeding eighteen months and certainly hadn’t heard anything from them. By this time, I was almost able to laugh about the whole incident.

But they were really back.

After the IAU decided to call round things dwarf planets, Easterbunny and Santa were eligible for real names, too, and the Spanish astronomers quickly submitted a name for Santa—because, of course, the discoverers get to name their discovery.

Rumor had it that the IAU was going to act swiftly, so Chad, David, and I quickly consulted and came up with our own name: Haumea, after the Hawaiian goddess of childbirth. Like the name Eris, the name Haumea seemed almost custom made for this object. The goddess Haumea gave birth to her many children by breaking them off from parts of her body. Santa the dwarf planet also had many children throughout the solar system that had broken off from its body. It seemed a perfect fit. And whatever the name was, it
definitely
should not be whatever the Spanish astronomers were submitting!

I wrote an impassioned letter to the various committees of the IAU proposing the name Haumea and also proposing names for two moons: Hi’iaka, the patron goddess of the Big Island, and Namaka, a water spirit, both daughters of Haumea. In the letter, I laid out—once again—all that had transpired. And then I explained why it was important that the IAU choose wisely which name to use. There was no question that eighteen months earlier someone had done something unseemly. If the Spanish astronomers had fraudulently claimed discovery of something that they had never actually discovered, it would be appropriate for the IAU to condemn such a thing. If, on the other hand,
their discovery was legitimate, they should be exonerated and I should be censured for making a spectacularly damaging wrongful accusation. Through choosing a name, the IAU would be officially choosing a side. I thought that the members of the IAU would not want to take sides and would instead pick a name themselves. I urged them not to cop out. No one else had the authority to render any type of meaningful verdict.

I sent in my letter and waited to see what would happen.

And I waited.

Lilah’s second birthday came around.

And I waited.

Lilah’s third birthday came around.

I was hoping that the IAU was taking its job quite seriously and had launched a multiyear investigation into what had happened. Apparently not. My inside sources tell me that nothing happened that entire time. Finally I got a tip that making a decision about Santa was just too hard and that perhaps we should try giving a name to Easterbunny as a way of getting things restarted.

Ah, Easterbunny. I had been thinking about it now for years. The names Sedna and Orcus (another large Kuiper belt object that we had turned up) had fit the characteristics of the objects’ orbits, and the names Eris and Haumea had practically fallen out of the sky at us. Even Quaoar, we felt, was a nice tribute to local mythology.

But what about Easterbunny? Unlike Santa, which has so many interesting characteristics that there were many possible names, Easterbunny has no obvious hook. Its surface is covered with large amounts of almost pure methane ice, a consequence of the fact that it is just a little smaller than Pluto and lacks enough gravity to hold a substantial nitrogen atmosphere, which is scientifically fascinating and all (really, it is) but not easily relatable
to terrestrial mythology. For a while I was working on coming up with a name related to the oracles at Delphi: Some people interpret the reported trancelike state of the oracles to be related to natural gas (methane) seeping out of the earth there. After some thought, I decided this theme was just dumb. Strike one.

I spent some time considering Easter- and equinox-related myths, as a tribute to the time of discovery. I was quite excited to learn about the pagan Eostre (or Oestre, or Oster, or many other spellings) after whom Easter is named, until I later realized that this mythology is perhaps itself mythological and, more important, that an asteroid had already been named after this goddess hundreds of years ago. Strike two.

Finally, in mythological desperation, I considered rabbit gods, of which there are many. Native American lore is full of hares, but they usually have names such as Hare or, better, Big Rabbit. I considered Manabozho, an Algonquin rabbit trickster god, but I must admit, perhaps superficially, that the “bozo” part at the end was a turnoff. There are many other names of rabbit gods, but the names just didn’t speak to me. Strike three.

These initial attempts had all happened long ago, and I had given up, figuring I would wait for the IAU decision on Santa. But now, with some prodding, I got back to work.

Suddenly, it dawned on me: There was a potentially interesting small island in the South Pacific that I hadn’t looked into before. I wasn’t familiar with the mythology of the island, so I had to look it up, and I found Makemake (pronounced Hawaiian style as “mah-kay mah-kay”), the chief god, the creator of humanity, and the god of fertility. I had discovered Easterbunny during the time that Diane was pregnant with Lilah. Easterbunny was the last of these discoveries. I have the distinct memory of feeling a fertile abundance pouring out of the entire
universe during that time. Easterbunny was part of that. Easterbunny would be Makemake, the fertility god of the island of Rapa Nui.

Rapa Nui was first visited by Europeans on Easter Sunday, 1722, precisely 283 years before the discovery of the Kuiper belt object now known as Makemake. Because of this first visit, the island is known in Spanish (it is a territory of Chile) as Isla de Pascua, but around here, it is far better known by its English name of Easter Island.

•   •   •

The name Makemake was accepted quite quickly and with a modest fanfare by the IAU; as predicted, a decision on Santa was soon rendered, only two years after the initial proposals had been submitted. This time there was no fanfare, no press release, no official pronouncements. The name just appeared on the official IAU list of names one day as Haumea. Three years after the Spanish astronomers either did or did not fraudulently steal our discovery, we were officially vindicated by the IAU, which accepted our name, signaling that we appropriately deserved the credit.

Sort of.

On the IAU’s list, next to the newly added name Haumea, in the space reserved for the name of the discoverers, is a big blank spot. Haumea, unique among all objects in the outer solar system, has no discoverer. It simply exists.

Oddly, though, for an object that no one discovered, it does have
place
of discovery listed. While the name of the object is Hawaiian, based on a proposal by astronomers from California, Haumea was officially discovered at a small telescope in Spain. By nobody.

What does any of this mean, officially? Mostly, I think, that
the IAU didn’t try too hard to figure anything out. Probably the majority of whatever committee was voting thought my version of the story was the most plausible, but there were enough dissenters that a decision was made to soften the pronouncement by listing no discoverer and by backhandedly acknowledging the Spanish claim.

I am disappointed that they made no real effort to figure out what happened, at least as far as I can tell. No one ever asked me anything or requested extra information from me. I suspect the same is true of the Spanish side. In the end, this is as good as it will get. I will never know for sure what actually took place in those two days before the Spanish astronomers announced their discovery.